from django.shortcuts import render, get_object_or_404
from django.http import HttpResponse, Http404, HttpResponseRedirect
from django.urls import reverse
from .models import Question, Choice
from django.views import generic
from django.utils import timezone


class IndexView(generic.ListView):
    template_name = 'polls/index.html'
    context_object_name = 'lasted_question_list'

    def get_queryset(self):
        # pub_date__lte=timezone.now() 是判断pub_date小于等于当前时间
        return Question.objects.filter(pub_date__lte=timezone.now()).order_by("-pub_date")[:5]


class DetailView(generic.DetailView):
    model = Question
    template_name = 'polls/detail.html'

    def get_queryset(self):
        return Question.objects.filter(pub_date__lte=timezone.now())


class ResultsView(generic.DetailView):
    model = Question
    template_name = 'polls/results.html'


def index(request):
    # polls的默认页面。会显示待投票的问题的列表.
    lastest_question_list = Question.objects.order_by("-pub_date")[:5]

    # 不推荐的做法是。在view中。把数据显示方式硬编码
    # output = ','.join([q.question_text for q in lastest_question_list])
    # return HttpResponse(output)

    # 较为复杂的使用模板文件的方式
    # template = loader.get_template("polls/index.html")
    # context = {
    #     "lasted_question_list": lastest_question_list
    # }
    # return HttpResponse(template.render(context, request))

    # 较为简单的使用模板文件的方式
    context = {
        "lasted_question_list": lastest_question_list
    }
    return render(request, "polls/index.html", context)


def bio(request, username):
    return HttpResponse("Hello, %s" % username)


def num(request, num):
    return HttpResponse("number is %s" % num)


def bio2(request, username):
    return HttpResponse("bio2's username=%s" % username)


def detail(request, question_id):
    # question = get_object_or_404(Question, pk=question_id)
    try:
        question = Question.objects.get(pk=question_id)
    except Question.DoesNotExist:
        raise Http404("您查找的这个问题并不存在。请确认您传入的问题编号是否正确")
    return render(request, "polls/detail.html", {"question": question})


def results(request, question_id):
    question = get_object_or_404(Question, pk=question_id)
    return render(request, "polls/results.html", {'question': question})


def vote(request, question_id):
    # get_object_or_404 抛出的404不能自定义提示内容。
    question = get_object_or_404(Question, pk=question_id)
    try:
        # request.POST可以获取到所有表单提交的数据
        print(request.POST)
        selected_choice = question.choice_set.get(pk=request.POST['choice'])
    except (KeyError, Choice.DoesNotExist):
        return render(request, "polls/detail.html", {
            'question': question,
            'error_message': "您投票的选项不存在或不正确"
        })
    else:
        selected_choice.votes += 1
        selected_choice.save()
        # HttpResponseRedirect可以跳转到指定地址
        # reverse方法可以获取指定url name的地址
        return HttpResponseRedirect(reverse('polls:results', args=(question.id, )))



